A data service for the distribution of data could include a presence information service, a location information service, among others. Distribution of data from a data service can be a difficult problem in both wired and wireless networks. The present disclosure refers to a presence service as an exemplary data service. The use of a presence service is not meant to be limiting, and other data services would be apparent to those skilled in the art.
For a presence service, distribution of presence data can be problematic because presence information can become verbose, particularly when taking into account the subtle nuances for the state of presentities. Verbose communication leads to increased traffic for the network, resulting in less bandwidth being available for other terminals, or reduced service offerings available for each terminal. If the terminal is a wireless device, increased verbosity further leads to increased battery usage since a receiver on the device needs to be turned on for longer periods.
Verbose communication also adds considerable complexity to a client application running on a terminal, among other factors.
Complexity also exists for a presentity needing to ‘identify’ and authorize possible watchers in current systems.
Various solutions exist to distribute data, including the Extensible Messaging and Presence Protocol (XMPP). XMPP is a protocol evolved from an instant messaging platform known as “Jabber” and defines an extensible markup language (XML) based protocol for the exchange of presence information between a presentity and a watcher. XMPP makes use of a roster mechanism for the management of contact lists. The XML protocol is not optimized for transport, particularly in a wireless network realization.
A second solution is the Open Mobile Alliance (OMA) presence enabler. The OMA presence enabler defines a Session Initiation Protocol (SIP) based protocol for the exchange of presence information between a presentity and a watcher. The OMA presence enabler makes use of information elements, and further permits extension of these information elements based on the Engineering Task Force (IETF) specified PIDF/RPID presence data models. The information elements are protocol independent and do not provide specific directives to the underlying transport layer to optimize delivery. The SIP protocol is a chatty protocol intended primarily for the wired domain and was originally designed for use in wire-line voice over internet protocol (VOIP)/call control applications.